A technician for Boeing confirmed to NYPD detectives that the wreckage is a “trailing edge flap actuation support structure from a Boeing 767,” NYPD spokesman Paul Browne said in a release.

The wreckage, believed to be from one of two Boeing 767 airliners destroyed on Sept. 11, 2001, was found last week wedged behind a lower Manhattan building.

Surveyors inspecting the back of 51 Park Place, several blocks from Ground Zero, found the rusted plane part with a Boeing identification number and other debris wedged between the buildings, police said.

Police believe the flap is from one of the two planes that struck the World Trade Center, but have not been able to determine which plane, Browne said.

NYPD

Machinery apparently from one of the commercial airliners destroyed on September 11, 2001, was discovered last week.

The flap is believed to be from the right wing of the plane, according to a sketch released by the NYPD.

The NYPD released a video that shows the flap wedged between concrete walls behind the Park 51 building, with several yellow police evidence markers place on it.

Browne said the NYPD is working with the Office of the Chief Medical Examiner, which will be sifting soil at the location for any human remains.

Ellen Borakove, a spokeswoman for the Office of the Chief Medical Examiner, said anthropologists will begin sifting behind Park 51 beginning at 8 a.m. Tuesday. The investigation is expected to take two days.

Police expect the sifting to be complete by Wednesday. At that point, officers with the NYPD Emergency Service Unit are expected to take the flap support structure into custody and store it with the department’s property clerk, where it will remain until a decision is made about where to put it permanently.

Browne cleared up speculation about a rope that was alongside the debris. Interviews Monday with detectives found that one of the first responding police officers “used rope that he found on the ground nearby to wrap around the aircraft part in order to move it in such a way as to look for its serial number or other identifiers,” Browne said.

It is unclear where the wreckage may end up. Federal investigators usually take possession of plane parts found following a crash, but pieces of wreckage recovered from 9/11 aircrafts have been treated as historical artifacts and become part of museum collections, Browne said.

The collection at the New York State Museum in Albany has a large piece of landing gear that went through the roof and landed in the basement at the Park 51 location.